1/* 2 * drivers/cpufreq/cpufreq_conservative.c 3 * 4 * Copyright (C) 2001 Russell King 5 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. 6 * Jun Nakajima <jun.nakajima@intel.com> 7 * (C) 2009 Alexander Clouter <alex@digriz.org.uk> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14#include <linux/slab.h> 15#include "cpufreq_governor.h" 16 17/* Conservative governor macros */ 18#define DEF_FREQUENCY_UP_THRESHOLD (80) 19#define DEF_FREQUENCY_DOWN_THRESHOLD (20) 20#define DEF_FREQUENCY_STEP (5) 21#define DEF_SAMPLING_DOWN_FACTOR (1) 22#define MAX_SAMPLING_DOWN_FACTOR (10) 23 24static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info); 25 26static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners, 27 struct cpufreq_policy *policy) 28{ 29 unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100; 30 31 /* max freq cannot be less than 100. But who knows... */ 32 if (unlikely(freq_target == 0)) 33 freq_target = DEF_FREQUENCY_STEP; 34 35 return freq_target; 36} 37 38/* 39 * Every sampling_rate, we check, if current idle time is less than 20% 40 * (default), then we try to increase frequency. Every sampling_rate * 41 * sampling_down_factor, we check, if current idle time is more than 80% 42 * (default), then we try to decrease frequency 43 * 44 * Any frequency increase takes it to the maximum frequency. Frequency reduction 45 * happens at minimum steps of 5% (default) of maximum frequency 46 */ 47static void cs_check_cpu(int cpu, unsigned int load) 48{ 49 struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, cpu); 50 struct cpufreq_policy *policy = dbs_info->cdbs.cur_policy; 51 struct dbs_data *dbs_data = policy->governor_data; 52 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 53 54 /* 55 * break out if we 'cannot' reduce the speed as the user might 56 * want freq_step to be zero 57 */ 58 if (cs_tuners->freq_step == 0) 59 return; 60 61 /* Check for frequency increase */ 62 if (load > cs_tuners->up_threshold) { 63 dbs_info->down_skip = 0; 64 65 /* if we are already at full speed then break out early */ 66 if (dbs_info->requested_freq == policy->max) 67 return; 68 69 dbs_info->requested_freq += get_freq_target(cs_tuners, policy); 70 71 if (dbs_info->requested_freq > policy->max) 72 dbs_info->requested_freq = policy->max; 73 74 __cpufreq_driver_target(policy, dbs_info->requested_freq, 75 CPUFREQ_RELATION_H); 76 return; 77 } 78 79 /* if sampling_down_factor is active break out early */ 80 if (++dbs_info->down_skip < cs_tuners->sampling_down_factor) 81 return; 82 dbs_info->down_skip = 0; 83 84 /* Check for frequency decrease */ 85 if (load < cs_tuners->down_threshold) { 86 unsigned int freq_target; 87 /* 88 * if we cannot reduce the frequency anymore, break out early 89 */ 90 if (policy->cur == policy->min) 91 return; 92 93 freq_target = get_freq_target(cs_tuners, policy); 94 if (dbs_info->requested_freq > freq_target) 95 dbs_info->requested_freq -= freq_target; 96 else 97 dbs_info->requested_freq = policy->min; 98 99 __cpufreq_driver_target(policy, dbs_info->requested_freq, 100 CPUFREQ_RELATION_L); 101 return; 102 } 103} 104 105static void cs_dbs_timer(struct work_struct *work) 106{ 107 struct cs_cpu_dbs_info_s *dbs_info = container_of(work, 108 struct cs_cpu_dbs_info_s, cdbs.work.work); 109 unsigned int cpu = dbs_info->cdbs.cur_policy->cpu; 110 struct cs_cpu_dbs_info_s *core_dbs_info = &per_cpu(cs_cpu_dbs_info, 111 cpu); 112 struct dbs_data *dbs_data = dbs_info->cdbs.cur_policy->governor_data; 113 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 114 int delay = delay_for_sampling_rate(cs_tuners->sampling_rate); 115 bool modify_all = true; 116 117 mutex_lock(&core_dbs_info->cdbs.timer_mutex); 118 if (!need_load_eval(&core_dbs_info->cdbs, cs_tuners->sampling_rate)) 119 modify_all = false; 120 else 121 dbs_check_cpu(dbs_data, cpu); 122 123 gov_queue_work(dbs_data, dbs_info->cdbs.cur_policy, delay, modify_all); 124 mutex_unlock(&core_dbs_info->cdbs.timer_mutex); 125} 126 127static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val, 128 void *data) 129{ 130 struct cpufreq_freqs *freq = data; 131 struct cs_cpu_dbs_info_s *dbs_info = 132 &per_cpu(cs_cpu_dbs_info, freq->cpu); 133 struct cpufreq_policy *policy; 134 135 if (!dbs_info->enable) 136 return 0; 137 138 policy = dbs_info->cdbs.cur_policy; 139 140 /* 141 * we only care if our internally tracked freq moves outside the 'valid' 142 * ranges of frequency available to us otherwise we do not change it 143 */ 144 if (dbs_info->requested_freq > policy->max 145 || dbs_info->requested_freq < policy->min) 146 dbs_info->requested_freq = freq->new; 147 148 return 0; 149} 150 151/************************** sysfs interface ************************/ 152static struct common_dbs_data cs_dbs_cdata; 153 154static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data, 155 const char *buf, size_t count) 156{ 157 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 158 unsigned int input; 159 int ret; 160 ret = sscanf(buf, "%u", &input); 161 162 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) 163 return -EINVAL; 164 165 cs_tuners->sampling_down_factor = input; 166 return count; 167} 168 169static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf, 170 size_t count) 171{ 172 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 173 unsigned int input; 174 int ret; 175 ret = sscanf(buf, "%u", &input); 176 177 if (ret != 1) 178 return -EINVAL; 179 180 cs_tuners->sampling_rate = max(input, dbs_data->min_sampling_rate); 181 return count; 182} 183 184static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf, 185 size_t count) 186{ 187 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 188 unsigned int input; 189 int ret; 190 ret = sscanf(buf, "%u", &input); 191 192 if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) 193 return -EINVAL; 194 195 cs_tuners->up_threshold = input; 196 return count; 197} 198 199static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf, 200 size_t count) 201{ 202 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 203 unsigned int input; 204 int ret; 205 ret = sscanf(buf, "%u", &input); 206 207 /* cannot be lower than 11 otherwise freq will not fall */ 208 if (ret != 1 || input < 11 || input > 100 || 209 input >= cs_tuners->up_threshold) 210 return -EINVAL; 211 212 cs_tuners->down_threshold = input; 213 return count; 214} 215 216static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data, 217 const char *buf, size_t count) 218{ 219 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 220 unsigned int input, j; 221 int ret; 222 223 ret = sscanf(buf, "%u", &input); 224 if (ret != 1) 225 return -EINVAL; 226 227 if (input > 1) 228 input = 1; 229 230 if (input == cs_tuners->ignore_nice_load) /* nothing to do */ 231 return count; 232 233 cs_tuners->ignore_nice_load = input; 234 235 /* we need to re-evaluate prev_cpu_idle */ 236 for_each_online_cpu(j) { 237 struct cs_cpu_dbs_info_s *dbs_info; 238 dbs_info = &per_cpu(cs_cpu_dbs_info, j); 239 dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j, 240 &dbs_info->cdbs.prev_cpu_wall, 0); 241 if (cs_tuners->ignore_nice_load) 242 dbs_info->cdbs.prev_cpu_nice = 243 kcpustat_cpu(j).cpustat[CPUTIME_NICE]; 244 } 245 return count; 246} 247 248static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf, 249 size_t count) 250{ 251 struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; 252 unsigned int input; 253 int ret; 254 ret = sscanf(buf, "%u", &input); 255 256 if (ret != 1) 257 return -EINVAL; 258 259 if (input > 100) 260 input = 100; 261 262 /* 263 * no need to test here if freq_step is zero as the user might actually 264 * want this, they would be crazy though :) 265 */ 266 cs_tuners->freq_step = input; 267 return count; 268} 269 270show_store_one(cs, sampling_rate); 271show_store_one(cs, sampling_down_factor); 272show_store_one(cs, up_threshold); 273show_store_one(cs, down_threshold); 274show_store_one(cs, ignore_nice_load); 275show_store_one(cs, freq_step); 276declare_show_sampling_rate_min(cs); 277 278gov_sys_pol_attr_rw(sampling_rate); 279gov_sys_pol_attr_rw(sampling_down_factor); 280gov_sys_pol_attr_rw(up_threshold); 281gov_sys_pol_attr_rw(down_threshold); 282gov_sys_pol_attr_rw(ignore_nice_load); 283gov_sys_pol_attr_rw(freq_step); 284gov_sys_pol_attr_ro(sampling_rate_min); 285 286static struct attribute *dbs_attributes_gov_sys[] = { 287 &sampling_rate_min_gov_sys.attr, 288 &sampling_rate_gov_sys.attr, 289 &sampling_down_factor_gov_sys.attr, 290 &up_threshold_gov_sys.attr, 291 &down_threshold_gov_sys.attr, 292 &ignore_nice_load_gov_sys.attr, 293 &freq_step_gov_sys.attr, 294 NULL 295}; 296 297static struct attribute_group cs_attr_group_gov_sys = { 298 .attrs = dbs_attributes_gov_sys, 299 .name = "conservative", 300}; 301 302static struct attribute *dbs_attributes_gov_pol[] = { 303 &sampling_rate_min_gov_pol.attr, 304 &sampling_rate_gov_pol.attr, 305 &sampling_down_factor_gov_pol.attr, 306 &up_threshold_gov_pol.attr, 307 &down_threshold_gov_pol.attr, 308 &ignore_nice_load_gov_pol.attr, 309 &freq_step_gov_pol.attr, 310 NULL 311}; 312 313static struct attribute_group cs_attr_group_gov_pol = { 314 .attrs = dbs_attributes_gov_pol, 315 .name = "conservative", 316}; 317 318/************************** sysfs end ************************/ 319 320static int cs_init(struct dbs_data *dbs_data) 321{ 322 struct cs_dbs_tuners *tuners; 323 324 tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); 325 if (!tuners) { 326 pr_err("%s: kzalloc failed\n", __func__); 327 return -ENOMEM; 328 } 329 330 tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; 331 tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; 332 tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; 333 tuners->ignore_nice_load = 0; 334 tuners->freq_step = DEF_FREQUENCY_STEP; 335 336 dbs_data->tuners = tuners; 337 dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * 338 jiffies_to_usecs(10); 339 mutex_init(&dbs_data->mutex); 340 return 0; 341} 342 343static void cs_exit(struct dbs_data *dbs_data) 344{ 345 kfree(dbs_data->tuners); 346} 347 348define_get_cpu_dbs_routines(cs_cpu_dbs_info); 349 350static struct notifier_block cs_cpufreq_notifier_block = { 351 .notifier_call = dbs_cpufreq_notifier, 352}; 353 354static struct cs_ops cs_ops = { 355 .notifier_block = &cs_cpufreq_notifier_block, 356}; 357 358static struct common_dbs_data cs_dbs_cdata = { 359 .governor = GOV_CONSERVATIVE, 360 .attr_group_gov_sys = &cs_attr_group_gov_sys, 361 .attr_group_gov_pol = &cs_attr_group_gov_pol, 362 .get_cpu_cdbs = get_cpu_cdbs, 363 .get_cpu_dbs_info_s = get_cpu_dbs_info_s, 364 .gov_dbs_timer = cs_dbs_timer, 365 .gov_check_cpu = cs_check_cpu, 366 .gov_ops = &cs_ops, 367 .init = cs_init, 368 .exit = cs_exit, 369}; 370 371static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy, 372 unsigned int event) 373{ 374 return cpufreq_governor_dbs(policy, &cs_dbs_cdata, event); 375} 376 377#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 378static 379#endif 380struct cpufreq_governor cpufreq_gov_conservative = { 381 .name = "conservative", 382 .governor = cs_cpufreq_governor_dbs, 383 .max_transition_latency = TRANSITION_LATENCY_LIMIT, 384 .owner = THIS_MODULE, 385}; 386 387static int __init cpufreq_gov_dbs_init(void) 388{ 389 return cpufreq_register_governor(&cpufreq_gov_conservative); 390} 391 392static void __exit cpufreq_gov_dbs_exit(void) 393{ 394 cpufreq_unregister_governor(&cpufreq_gov_conservative); 395} 396 397MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>"); 398MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " 399 "Low Latency Frequency Transition capable processors " 400 "optimised for use in a battery environment"); 401MODULE_LICENSE("GPL"); 402 403#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE 404fs_initcall(cpufreq_gov_dbs_init); 405#else 406module_init(cpufreq_gov_dbs_init); 407#endif 408module_exit(cpufreq_gov_dbs_exit); 409